$ { \left[\begin{array}{rr}{1} & {2} \\ {0} & {4} \\ {-1} & {-1}\end{array}\right]-\left[\begin{array}{rr}{-1} & {-1} \\ {4} & {1} \\ {3} & {1}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{-1} & {2}-{-1} \\ {0}-{4} & {4}-{1} \\ {-1}-{3} & {-1}-{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{2} & {3} \\ {-4} & {3} \\ {-4} & {-2}\end{array}\right]}$